To balance the inertia or weight of moving loads or masses, use is generally made of mechanical counterweights and/or elastic systems which allow for a partial compensation of the weight of a body and the moving of even very heavy loads, with comparatively small applied forces in relation to the load to be balanced.
The use of mechanical counterweighting and/or elastic balancing systems is considerably limited in that these systems are normally bulky or do not allow an adequate balancing action of the load, or behaviour, which is independent or unrestricted by the load to be controlled and its displacement direction.
In particular, the need to move masses with acceptable speeds and accelerations, at times requires the use of high power levels, with consequently expensive and bulky drives and complex control systems.
Pneumatic or hydraulic systems which use standard pressure-regulating valves are not able to achieve an effective balancing due to the impossibility of modifying the hydraulic or pneumatic action to balance the load while maintaining it under constant and strictly controlled conditions.
The object of the present invention is to provide a pressure equaliser device in a hydraulic or pneumatic load balancing system, whose action is totally constant and independent of the mass or of the load to be controlled, and cannot be influenced by the moving direction of the load itself.
A further object of the present invention is to provide a pressure equaliser device for load balancing which is highly reliable, simple in construction, economical and with minimal overall dimensions.
A further object again of the present invention is to provide a pressure equaliser device for a load balancing system, which is able to maintain an exactly constant balancing pressure, ensuring fast feed and venting or pressure releasing of the pressurised fluid without causing hazardous back pressures which otherwise could unbalance the load or slow down its movement.